美国塔芙茨 (Tufts) 大学政治科学系教授 Elizabeth J. Remick (雷莎蓓) 的新作《建构地方政权: 民国和后毛泽东时代的中国》(Building Local States: China During the Republi can and Post Mao Eras) 一书, 是本年度哈佛大学出版社...美国塔芙茨 (Tufts) 大学政治科学系教授 Elizabeth J. Remick (雷莎蓓) 的新作《建构地方政权: 民国和后毛泽东时代的中国》(Building Local States: China During the Republi can and Post Mao Eras) 一书, 是本年度哈佛大学出版社亚洲研究中心推出的中国政治科学研究的力作。作者综合运用政治科学、历史学、人类学及跨文化、跨区域比较研究的方法, 以中国学研究为对象, 在方法、内容、理论范式转换等广泛层面上展开对话与探讨。该书关注到国家领域中的一个重要问题———税收与公共财政, 探讨了地方政权在这两个时期的构建过程。本刊现发表对该书作者雷莎蓓教授的访谈, 在访谈中, 雷莎蓓教授以其亲身经历揭示了美国大学与学术机构的科层体制, 并对因泾渭分明的系科设置造成难以逾越的研究障碍与观念歧异做出了解答; 还就学者个人学术训练背景、历史与民族志研究等诸多问题展开了广泛的对话与探讨。这些问题都是很有意义的, 给人以启迪, 让人们深思。展开更多
Most of the current computing methods used to determine the magnetic field of a uniformly magnetized cuboid assume that the observation point is located in the upper half space without a source. However, such methods ...Most of the current computing methods used to determine the magnetic field of a uniformly magnetized cuboid assume that the observation point is located in the upper half space without a source. However, such methods may generate analytical singularities for conditions of undulating terrain. Based on basic geomagnetic field theories, in this study an improved magnetic field expression is derived using an integration method of variable substitution, and all singularity problems for the entire space without a source are discussed and solved. This integration process is simpler than that of previous methods, and final integral results with a more uniform form. AT at all points in the source-flee space can be calculated without requiring coordinate transformation; thus forward modeling is also simplified. Corresponding model tests indicate that the new magnetic field expression is more correct because there is no analytical singularity and can be used with undulating terrain.展开更多
In order to investigate the surface deformation caused by coal mining and to reduce environmental damage, more accurate information of dynamic subsidence basins, caused by coal mining, is needed. Based on theological ...In order to investigate the surface deformation caused by coal mining and to reduce environmental damage, more accurate information of dynamic subsidence basins, caused by coal mining, is needed. Based on theological theory, we discuss surface deformation mechanism of dynamic subsidence on the assumption that both the roof and the coal seam are visco-elastic media, put forward the idea that the principle of surface deformation is similar to that of roofs, except for their parameters. Therefore, a surface deforma- tion equation can be obtained, given the equation of the roof deformation derived.from using a HIM rhe- ological model. In the end, we apply the equation of surface deformation as a practical subsidence prediction in a coal mine. Given the theologic properties of a rock mass, the results of our research of a dynamic subsidence basin can predict the development of surface deformation as a function of time, which is more important than the ultimate subsidence itself. The results indicate that using rheological theory to calculate the deformation of a dynamic subsidence basin is suitable and provides some reference for surface deformation of dynamic subsidence basins.展开更多
Photogrammetry, as a tool for monitoring underground mine deformation, is an alternative to traditional point measurement devices, and may be capable of accurate measurements in situations where technolo- gies such as...Photogrammetry, as a tool for monitoring underground mine deformation, is an alternative to traditional point measurement devices, and may be capable of accurate measurements in situations where technolo- gies such as laser scanning are unsuited, undesired, or cost-prohibitive. An underground limestone mine in Ohio is used as a test case for monitoring of structurally unstable pillars. Seven pillars were pho- tographed over in a 63 day period, punctuated by four visits. Using photogrammetry, point clouds of the mine geometry were obtained and triangulation surfaces were generated to determine volumes of change over time. Pillar spaUing in the range of 0.29-4.03 m3 of rock on individual rib faces was detected. Isolated incidents of rock expansion prior to failure, and the isolated failure of a weak shale band were also observed. Much of the pillars remained unchanged during the monitoring period, which is indicative of proper alignment in the triangulated surfaces. The photographs of some ribs were of either too poor quality or had insufficient overlap, and were not included. However, photogrammetry was successfully aonlied to multiole ribs in auantifving the oillar geometrv change over time.展开更多
文摘美国塔芙茨 (Tufts) 大学政治科学系教授 Elizabeth J. Remick (雷莎蓓) 的新作《建构地方政权: 民国和后毛泽东时代的中国》(Building Local States: China During the Republi can and Post Mao Eras) 一书, 是本年度哈佛大学出版社亚洲研究中心推出的中国政治科学研究的力作。作者综合运用政治科学、历史学、人类学及跨文化、跨区域比较研究的方法, 以中国学研究为对象, 在方法、内容、理论范式转换等广泛层面上展开对话与探讨。该书关注到国家领域中的一个重要问题———税收与公共财政, 探讨了地方政权在这两个时期的构建过程。本刊现发表对该书作者雷莎蓓教授的访谈, 在访谈中, 雷莎蓓教授以其亲身经历揭示了美国大学与学术机构的科层体制, 并对因泾渭分明的系科设置造成难以逾越的研究障碍与观念歧异做出了解答; 还就学者个人学术训练背景、历史与民族志研究等诸多问题展开了广泛的对话与探讨。这些问题都是很有意义的, 给人以启迪, 让人们深思。
基金supported by China Geological Survey Northeastern Tarim Aeromagnetic and Aerogravity comprehensive survey project(No.12120115039401)
文摘Most of the current computing methods used to determine the magnetic field of a uniformly magnetized cuboid assume that the observation point is located in the upper half space without a source. However, such methods may generate analytical singularities for conditions of undulating terrain. Based on basic geomagnetic field theories, in this study an improved magnetic field expression is derived using an integration method of variable substitution, and all singularity problems for the entire space without a source are discussed and solved. This integration process is simpler than that of previous methods, and final integral results with a more uniform form. AT at all points in the source-flee space can be calculated without requiring coordinate transformation; thus forward modeling is also simplified. Corresponding model tests indicate that the new magnetic field expression is more correct because there is no analytical singularity and can be used with undulating terrain.
基金Financial support for this research, provided by the National Natural Science Foundation of China (Nos.50804020 and 50974070)the Doctor Initial Fund of Liaoning Provincial Science and Technology Department (No.20081103)the Key Laboratory Fund of Liaoning Province (No. LS2010074)
文摘In order to investigate the surface deformation caused by coal mining and to reduce environmental damage, more accurate information of dynamic subsidence basins, caused by coal mining, is needed. Based on theological theory, we discuss surface deformation mechanism of dynamic subsidence on the assumption that both the roof and the coal seam are visco-elastic media, put forward the idea that the principle of surface deformation is similar to that of roofs, except for their parameters. Therefore, a surface deforma- tion equation can be obtained, given the equation of the roof deformation derived.from using a HIM rhe- ological model. In the end, we apply the equation of surface deformation as a practical subsidence prediction in a coal mine. Given the theologic properties of a rock mass, the results of our research of a dynamic subsidence basin can predict the development of surface deformation as a function of time, which is more important than the ultimate subsidence itself. The results indicate that using rheological theory to calculate the deformation of a dynamic subsidence basin is suitable and provides some reference for surface deformation of dynamic subsidence basins.
文摘Photogrammetry, as a tool for monitoring underground mine deformation, is an alternative to traditional point measurement devices, and may be capable of accurate measurements in situations where technolo- gies such as laser scanning are unsuited, undesired, or cost-prohibitive. An underground limestone mine in Ohio is used as a test case for monitoring of structurally unstable pillars. Seven pillars were pho- tographed over in a 63 day period, punctuated by four visits. Using photogrammetry, point clouds of the mine geometry were obtained and triangulation surfaces were generated to determine volumes of change over time. Pillar spaUing in the range of 0.29-4.03 m3 of rock on individual rib faces was detected. Isolated incidents of rock expansion prior to failure, and the isolated failure of a weak shale band were also observed. Much of the pillars remained unchanged during the monitoring period, which is indicative of proper alignment in the triangulated surfaces. The photographs of some ribs were of either too poor quality or had insufficient overlap, and were not included. However, photogrammetry was successfully aonlied to multiole ribs in auantifving the oillar geometrv change over time.
